1. Field of the Invention
The invention concerns a method for controlling a thick matter pump, which comprises two conveyance cylinders with openings in communication with a material reservoir and with conveyance pistons operated in counterstroke, as well as a branch pipe provided within the material reservoir and having its inlet alternatingly in communication with the openings of the conveyance cylinders while leaving open the respective other opening and having its outlet in communication with the conveyance conduit, wherein during pumping operations thick matter is sucked from the material reservoir into the open conveyance cylinder and pumped via the other conveyance cylinder temporarily in communication with the branch pipe to the outlet conveyance conduit with building up of a thick matter column in the conveyance conduit.
2. Description of the Related Art
Although thick matter pumps of this type are suitable for conveyance of various types of pumpable thick material, additional considerable technical and economic factors are involved in the conveyance of liquid concrete. The following embodiments are thus directed specifically to the conveyance of liquid concrete, but it should be understood that the invention is not thereby being limited thereto.
Thick matter pumps can be provided on stationary or mobile frameworks. Primarily in mobile concrete pumps the conveyance conduit is directed along a distribution boom which may be an articulated boom and includes a terminal hose in the area of its outlet. The material reservoir of the concrete pump is conventionally supplied with liquid concrete via a mobile concrete mixer. During the waiting time, while waiting for the next mobile cement mixer or during repositioning of the distribution boom to a different application location, the pumps are routinely paused, and the concrete pump is out of operation. At this time there is concern that the concrete which is at rest can begin setting or hardening. This applies in particular in the case of self-hardening concretes, in which a self-hardening from below builds up as a result of the off-gassing of air pores. During the pausing of the pumping there are thus undesired occurrences of hardening of concrete both in the conveyance system as well as in the material reservoir.